Obesity and physical inactivity will soon replace cigarette smoking as the leading cause of preventable death in the United States. A major factor is the replacement of physically active behaviors with sedentary consumption of electronic media. The Principal Investigator has developed wireless embedded technology making media access (television, computers, cell phones) contingent upon physical activity detected by automatic sensors. The method thus simultaneously decreases sedentary and increases active behaviors. Physical activity meeting a remotely programmable criterion results in the accretion of points that are transferable to electronic accounts maintained on devices regulating access to media. Importantly, the user need not be connected to the media device during the physical activity; thus, a wide variety of activities can be accommodated. The embedded processors enable the implementation of an individually-tailored reinforcement schedule allowing the user to begin an exercise program at their appropriate fitness level and progress incrementally toward a more rigorous goal through approximation. The Specific Aims of this application are to: 1) make improvements to the technology, 2) confirm the precision of the exercise sensors, 3) create objective measures using the sensors, 4) test the effect of the intervention in the laboratory, and 5) conduct home-based reliability tests.